<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
        <script>
            /* 
          运算符优先级:
                1.()
                2.单目运算 ++--
                3.算数运算符  + - * / % (先乘除后加减)
                4.比较运算符 > < >= <= != == ===
                5.逻辑运算符 && || (先&& 后||)
                6.三目运算 ? : (了解)
                7.赋值运算  = += -= *= /=


        技巧 : 一般通过逻辑运算符切割.
        */
        </script>
</body>
</html>